Assumptions

Your KMS hosts are running an server operating systems and not client operating system

You are planning on deploying Windows 8 and/or Windows Server 2012.

You may or may not have Office 2010 or 2013 configured for KMS activation

Important points

Windows 8 and Windows Server 2012 have the option of using Active Directory Based Activation (ADBA). This is where a domain joined computer looks for activation object in AD and is automatically activated.

ADBA requires AD DS be at the Windows Server 2012 schema level to store activation objects. Domain controllers running earlier versions of Windows Server can activate clients after their schemas have been updated using the Windows Server 2012 version of Adprep.exe.

Older operating systems will not be updated to support ADBA

There are 2 types of KMS host keys for Windows 8 and Windows Server 2012

Windows Server 2012 KMS Host Key (CSVLK): Activates all operating systems and will be the most common CSVLK you will activate

Configurations and Recommendations

The following are a few common configurations and options. This should not be considered an exhaustive list of possible solutions since every deployment can be slightly different and have different goals and planning needs. When considering options the important question is if you are willing to update your schema level using Adprep. If not then Active Directory Based Activation is off the table although you can always do it later. You also need to consider Office activation if you are using Office